In the photomechanical process, it is necessary to obtain a photographic characteristic of superhigh contrast (particularly, having a gamma of 10 or more) in order to achieve satisfactory reproduction of a continuous gradation by dot images or reproduction of a line image. Superhigh contrast has generally been obtained by using a combination of a light-sensitive material comprising a silver chloride emulsion or a silver chlorobromide emulsion having a high silver chloride content and a hydroquinone developer having an extremely low effective concentration, usually not more than 0.1 mol/l, of a sulfite ion (infectious developer). However, such an infectious developer is seriously labile due to its low sulfite ion concentration and cannot withstand preservation for more than 3 days.
An improved process for obtaining a superhigh contrast characteristic with a stable developer has been proposed in U.S. Pat. No. 4,224,401, etc., in which a specific hydrazine compound is used. According to this process, presence of a high concentration sulfite ion in a developer is permissible so that stability of the developer against air oxidation can be improved.
It has also been proposed in Japanese Patent Application (OPI) No. 106244/81 (the term "OPI" as used herein refers to a "published unexamined Japanese patent application") (which corresponds to U.S. Pat. No. 4,269,929) that an amine compound is added to the above-described developer containing a hydrazine compound in order to obtain a negative image having a high gamma value with a developer at a lower pH value, for example, at 10.8 to 11.4.
However, the above-described image formation process still involves a problem in that a superhigh contrast image is hardly obtained in the so-called rapid access processing which has recently enjoyed an increasing demand, i.e., an extremely rapid photographic processing generally requiring only from 90 to 120 seconds for total processing of from the start of development through drying to obtain a processed film with development processing completing within 15 to 60 seconds.